Spinneret



' stances.

Patented Nov. 23, 1943 UNITED STATES PATENT OFFICE SPINNERET Harold Whitehead, South Orange, N. J assignor to Baker & Company, Inc., Newark, N.' J., a corporation of New Jersey No Drawing. Application July 26, 1941,

Serial No. 404,202.

general and is concerned in particular with spin nerets for the formation of synthetic fibres and filaments such as. rayon, artificial silk, artificial wool and the like from organic and the like sub- In the manufacture of synthetic 'fibres and filaments by the viscose process a viscose solution is extruded through small orifices provided in .the spinneret usually formed in the shape of a cup. The bottom of a cup-shaped spinneret or the extrusion wall of the spinneret is provided with a plurality of extremely fine holes or ori-.

fices having, for instance, a diameter of .002" to .005". In many processes the viscous .material is extruded through the fine spinneret of, orifices under hydraulic pressure. At the same time the spinneretis 'subjectedto the chemical action of the basic viscose solution and of the acid coagulating bath. The orifice itself may be in the shape of astraight cylindrical hole, with surface of definite configuration. It is, therefore,

necessary to form such spinnerets of a construction material-which initially permits the formation of the extremely fine orifices with perfectly smooth and highly polished ,walls and which is capable of withstanding, over extended periods of time, any and all alterations of the perfect flow surface of the orifices and of the definite cross section of such orifices as the result of chemical attack, mechanical deformation under pressure, abrasion by the flowing masses of viscose or other viscous material and mechanical damage due to handling. The spinneret must also be such that it can withstand not only the impact of pressure as such but also the changing impacts of varying pressures.

Furthermore the viscous solution has a tendency to produce clogging of the orifices by creating deposits within the orifices whereby the effective diameter of the extrusionorifices is chan ed. It is now known that some materials possess more ability than others to counteract the tendency of the solution to create such deposits and produce. clogging and it is therefore highly desirable to construct spinnerets of such materials that will counteract such tendency as much as possible.

spinnerets for the production of synthetic fibres and filaments by the viscose process generally consist of precious metal, in particular of alloys of gold with platinum and alloys of platinum with rhodium. spinnerets 'of alloys of platinum and rhodium have, as pointed out in U. S. Letters Patent No. 2,135,611, a greater tendency to diminish clogging of and deposition within spinneret orifices than other spinnerets theretofore known and are therefore generally preferred today .to all other types of spinnerets.

I have found that spinnerets of alloys of platinum with rhodium and ruthenitun are excepmately 15% rhodium and not less than 0.5%

ruthenium and not more than approximately 10% ruthenium, the remainder being substan-'- tially platinum. I may, therefore, produce for instance, spinnerets consisting of such alloys of platinum with 5% rhodium and 5% ruthenium, 90% platinum with 7.5% rhodium and 2.5% ruthenium, 92.5% platinum with 5% rhodium and 2.5% ruthenium, or platinum with 3% rhodium and 2% ruthenium. It is not always it should not fall below about 75%. Likewise,

th. rhodium-ruthenium component should be, in its entirety, not less than 1.5% in any case and I recommend that preferably it should not fall below about 5% of the whole alloy.

The spinnerets according to my invention are admirably suited for the formation of synthetic fibres and filaments in such extrusion processes as the viscose process. The construction material of such spinnerets is such that the provision of intricate shapes, as for instance cups, is easily possible and that the formation of extremely fine holes to form the extrusion orifices can be accomplished easily with great accuracy. The walls of the orifice holes are perfectly smooth and highly polished due to the specific advantageous grain structure of the alloys. The flow surface of the spinneret orifices is therefore of high perfection permitting smooth and speedy flow of the viscous mass through the spinneret orifices. The hardness and mechanical strength of my spinnerets are great, and even in excess'of the hardness of comparable spinnerets of platinum rhodium alloys .or gold platinum alloys, whereby my spinnerets are possessed of high capacity to withstand abrasion by the flowing viscous masses, mechanical deformation by pressure, constant as well as varying, and damage due to handling. A further advantage of such spinnerets is that, due to their great strength and hardness, it is possible to manufacture them, if desired, of less wall thickness than is possible with other spinnerets, thereby decreasing the cost of such spinnerets. The inherent-cost of my spinnerets is also less than that of many other spinnerets due to the low specific gravity, and low price, of ruthenium.

I have further found that thespinnerets according to my invention have a surprising low I afi'inity for viscose and the like viscous substances, thereby reducing the tendency of such substances to form deposits on the extrusion walls and to produce clogging of the orifices,

higher content of rhodium.

nerets. Such spinnerets are useful for the spinning of such fibres and filaments of all desirable deniers and, due to their advantageous characteristics, are of particular usefulness in the spinning of the finer fibres and filaments. The

advantageous characteristics of my spinnerets are such that for instance in the formation of synthetic fibres and filaments by the viscose proc- 'ess a spinneret containing a given amount of rhodium and ruthenium is capable of duplicating, and even exceeding, the advantageous properties of platinum rhodium spinnerets of a like or even The spinnerets according to my invention may also contain small quantities of other metals so long as the advantageous properties of my spinnerets are not thereby substantially impaired.

What I claim is:

1. A spinneret for the production of synthetic fibres and filaments from viscose, consisting of an alloy of approximately 90% to 95% platinum, 3% to 7.5% rhodium, and 2% to 5% ruthenium.

2. A spinneret for the production of synthetic fibres and filaments from viscose, consisting of an alloy of approximately 92.5% platinum, 5% rhodium, and 2.5% ruthenium.

3. A spinneret of an alloy of platinum with rhodium and ruthenium, wherein the platinum thereby maintaining a highly constant and uniform cross section of the extrusion orifices for extended periods of time. Also the spinnerets according to my invention are highly resistant to chemical attack by the viscose and by the acid coagulating bath.

The spinnerets according to the present invention therefore can be operated in the formation of synthetic fibres and filaments. for extended periods of time without the necessity of cleaning the orifices, and are adapted to produce more uniform fibres and filaments than other spincomponent comprises at least about but not more than and the rhodium-ruthenium component comprises at least about 5% but not more than 25%.

4. A spinneret for the production of synthetic fibres and filaments from organic substances, consisting of an alloy of platinum rhodium ruthenium containing from 1% to 15% rhodium, from 0.5% to 10% ruthenium, and from {75% to 98.5% platinum.

HAROLD WHITEHEAD. 

